Generally speaking, it can be said that each golf club has a “sweet spot” for striking a golf ball. The sweet spot is typically located at or near the center of the face of the golf club and defines the location on the face of the golf club where it is most desirable to make contact with the golf ball during the golf swing. Striking the golf ball at the sweet spot generally results in the best overall trajectory, distance and direction of flight for the golf ball.
It should be understood that golf club manufacturers do not identify the location of the sweet spot on the face of golf clubs. One reason for this is that the sweet spot for any given golfer may actually be located at a slightly different location on the face of the golf club. The exact location of the sweet spot for any given golfer is dependent in part on the characteristics of the golfer's swing, including the swing plane of the golfer's swing, as well as on the physical characteristics of the golfer.
A variety of factors contribute to the proper execution of a golf swing. These factors include the stance assumed by the golfer, the distance between the golfer and the golf balls the balance of weight assumed by the golfer, the golfer's grip on the golf club, the rotation of the golfer's shoulders and hips, and the speed and path of the back-swing, the down-swing and the follow-through swing. Each of these factors ultimately affects the manner in which the golf club makes contact with the golf ball, including the location of impact between the golf ball and the golf club. A properly executed golf swing will generally result in the golf ball impacting the face of the golf club at or near the sweet spot. The resultant forces imposed upon the golf ball by the golf club will then cause the golf ball to acheive the best overall trajectory, distance, and direction of flight.
Golfers typically perfect their golf swing by taking golf lessons or through practice and repeated trial and error. In order for these practice sessions to be of the greatest value to the golfer, it is desirable to provide the golfer with information and feedback concerning the golfer's swing each time the golfer takes a practice swing. One source of information that is easily obtained by the golfer relates to the trajectory, distance traveled and direction of flight of the golf ball. This information can be easily obtained by the golfer through simple observation of the golf ball after it leaves the face of the golf club. Thus, for each swing, the golfer can easily observe whether or not the swing produced the desired results.
One way for a golfer to identify the location of the sweet spot on the face of a golf club is to first observe the flight pattern (e.g., trajectory, distance traveled and direction of flight) of the golf ball for each golf swing to determine the results produced by each swing, and then second, observe the location of impact between the golf ball and the face of the golf club for each golf swing to determine which impact locations correspond to the best overall results. Providing the golfer with proper feedback regarding the location of impact between the golf ball and the face of the golf club, therefore, in combination with the golfer's own observation of the flight pattern of the golf ball, allows the golfer to identify the location of the sweet spot on the face of the golf club and further enables the golfer to adjust his or her stance, swing and/or grip to insure that the golf ball repeatedly strikes the face of the golf club at or near the sweet spot.
It is desirable, therefore, in addition to the information obtained by the golfer through his or her own observation of the flight pattern of the golf ball, to provide accurate feedback to the golfer regarding the location of impact between the golf ball and the face of the golf club so that the golfer can make the proper adjustments to his or her golf swing.
Numerous devices and systems for providing such feedback are known in the prior art as evidenced by U.S. Pat. No. 5,779,556 issued to Cervantes et al. on Jul. 14, 1998; U.S. Pat. No. 5,142,309 issued to Lee on Aug. 25, 1992; U.S. Pat. No. 5,033,746 issued to Jones on Jul. 23, 1991; U.S. Pat. No. 4,974,851 issued to Closser et al. on Dec. 4, 1990; U.S. Pat. No. 3,806,132 issued to Brandell on Apr. 23, 1974; U.S. Pat. No. 3,754,764 issued to Manheck on Aug. 28, 1973; and U.S. Pat. No. 2,660,436 issued to Gorssman on Nov. 24, 1953.
These known prior art systems suffer from one or more deficiencies, however. For example, many of these prior art systems are complex in that they are comprised of numerous layers of different materials. Some, for example, include wax or waxy layers that may, under force, slip or move out of position and whose properties may change in very warm or very cool weather. Others include one or more layers of paper or paper by-products that can easily tear during impact or be damaged by moisture or water. Finally, others include smooth outer plastic layers designed to protect the inner waxy or paper layers. The outer plastic layers tend to have relatively low coefficients of surface friction. The smooth plastic outer layers, therefore, may not accurately replicate the grip that the club face would have had on the ball in the absence of the recording device.
Another problem with these prior art devices relates to re-usability. Most of the prior art devices are designed to be used once, or at most, only a few times before they must be replaced. In all but one of these prior art systems, the mark or image left by the golf ball cannot be erased and repeated use of the recording device results in multiple marks being left on the recording device. The one prior art device that does provide for erasure of the mark left by the golf ball (see U.S. Pat. No. 5,033,746) suffers from the other drawbacks discussed above.
It is desirable, therefore, to have a recording device that is simple in construction yet rugged enough to handle the forces imparted by a golf ball during impact with a golf club. It is also desirable to have a recording device that can tolerate moisture and changes in temperature without effecting performance. It is also desirable to have a recording device that has a contact surface with a coefficient of surface friction that can accurately replicate the grip that a golf club puts on a golf ball. It is also desirable to have a recording device that can be used over and over again, both in terms of its lasting durability and in terms of its ability to provide for the erasure of earlier impact marks and images.
Another type of prior art practice device for identifying the impact location between a ball and the face of a golf club involves the use of hook and loop type fastening systems and lightweight practice golf balls. Two such prior art devices are disclosed in U.S. Pat. No. 3,721,447 which issued to Louderback on Mar. 20, 1973 and U.S. Pat. No. 3,401,941 which issued to Hesidence on Sep. 17, 1968.
As previously mentioned, each of these prior art devices use a hook and loop type fastening system (one type of which is commonly known as “Velcro”) to identify the location of impact between a lightweight practice ball and the face of the golf club. In essence, one half of the hook and loop type fastener is applied to the face of the golf club and the other half is affixed to the practice ball. These devices work on the principle that upon impact between the practice ball and the face of the golf club, the practice ball will stick to the face of the golf club at the point of impact. Thus, the location of impact can be observed by simply viewing the stuck practice ball on the face of the golf club.
The prior art practice devices that incorporate a hook and loop type fastening system suffer from several major drawbacks, however. First, these prior art devices are not generally suited for use with real golf balls. Rather, they generally use lightweight practice golf balls such as lightweight hollow whiffe type golf balls. Regulation golf balls generally will not work with these prior art devices because they are too heavy and dense and simply will not remain stuck on the face of the golf club during and after the golf swing.
Second, a golfer using one of these prior art devices is not provided with any information regarding the trajectory, distance or direction of flight of the ball because the lightweight practice ball sticks to the face of the golf club. Without being able to observe what happened to the ball after it is hit, the golfer simply cannot evaluate the performance of his or her swing.
It is also desirable, therefore, to have a recording device suitable for use with real regulation golf balls. Preferably, the recording device will permit the golf ball to follow the same or substantially the same trajectory and direction of flight, and travel the same or substantially the same distance, as the golf ball would have traveled in the absence of the recording device. This will allow a golfer to obtain information regarding the end results produced by each golf swing in addition to providing the golfer with information regarding the impact location of the golf ball with the face of the golf club.